Social support and pet ownership, a nonhuman form of social support, have both been associated with increased coronary artery disease survival. The independent effects of pet ownership, social support, disease severity, and other psychosocial factors on 1 year survival after acute myocardial infarction are examined prospectively. The Cardiac Arrhythmia Suppression Trial provided physiologic data on a group of post-myocardial infarction patients with asymptomatic ventricular arrhythmias. An ancillary study provided psychosocial data, including pet ownership, social support, recent life events, future life events, anxiety, depression, coronary prone behavior, and expression of anger. Subjects (n = 424) were randomly selected from patients attending participating Cardiac Arrhythmia Suppression Trial sites and completed baseline psycho-social questionnaires. One year survival data were obtained from 369 patients (87%), of whom 112 (30.4%) owned pets and 20 (5.4%) died. Logistic regression indicates that high social support (p <0.068) and owning a pet (p = 0.085) tend to predict survival independent of physiologic severity and demographic and other psychosocial factors. Dog owners (n = 87, 1 died) are significantly less likely to die within 1 year than those who did not own dogs (n = 282, 19 died; p <0.05); amount of social support is also an independent predictor of survival (p = 0.065). Both pet ownership and social support are significant predictors of survival, independent of the effects of the other psychosocial factors and physiologic status. These data confirm and extend previous findings relating pet ownership and social support to survival among patients with coronary artery disease.